Inductor for heating an elongated, flanged workpiece

ABSTRACT

An inductor for inductively heating an elongated, flanged workpiece including two generally parallel conductors extending the length of the workpiece and a crossover conductor magnetically coupled with the flange. This crossover conductor includes two diverging legs connected by a generally arcuate portion so that the arcuate portion has a length substantially greater than the arcuate spacing between the parallel conductors.

United States Patent Vickers Mar. 14, 1972 [541 INDUCTOR FOR HEATING AN ELONGATED, FLANGED WORKPIECE [72] Inventor: Robert V. Vickers, Shaker Heights, Ohio [73] Assignee: Park-Ohio Industries, Inc., Cleveland,

Ohio

[22] Filed: May 14, 1970 [21] Appl. No.: 37,255

[52] 11.8. C1 ..2l9/10.79, 219/1043 [51] Int. Cl. ..H05b 9/02 [58] Field of Search ..2l9/l0.79, 10.43

[56] References Cited UNITED STATES PATENTS 3,188,440 6/1965 Wokas ..219/10.43 3,483,346 12/1969 Seulen et al ..2l9/10.79 X

FOREIGN PATENTS OR APPLICATIONS 710,426 6/1954 Great Britain ..219/ 10.43

Primary Examiner-.1. V. Truhe Assistant Examiner-Hugh D. Jaeger Attorney-Meyer, Tilberry and Body [57] ABSTRACT An inductor for inductively heating an elongated, flanged workpiece including two generally parallel conductors extending the length of the workpiece and a crossover conductor magnetically coupled with the flange. This crossover conductor includes two diverging legs connected by a generally arcuate portion so that the arcuate portion has a length substantially greater than the arcuate spacing between the parallel conductors. 1

2 Claims, 4 Drawing Figures PATENTEDMAR 14 m2 3,649,797

jgii 2 C A 36 ENTOR. ROBERT v. CKERS BY W. 7% 5 8 d ATTORNEYS l6 3 I IZOE 4 I I a 4 FIG 3 INDUCTOR FOR HEATING AN ELONGATED, FLANGED WORKPIECE The invention relates to the art of induction heating and more particularly to an inductor for inductively heating an elongated flanged workpiece.

This invention is particularly applicable for inductively heating an axle shaft having a flange on one end thereof, and it will be described with particular reference thereto; however, it 'should be appreciated that the invention has much broader applications and can be used for inductively heating a variety of elongated workpieces having a relatively long cylindrical portion and a flange adjacent one end thereof.

Recently, there has been a substantial amount of develop- .ment work directed toward an arrangement for inductively heating an axle shaft, which arrangement incorporates an inductor having two generally parallel conductors extending substantially the complete length of the axle shaft. These parallel conductors are connected by terminal crossover conductors to form an electrical loop. These crossover conductors do perform a heating function; however, it is not essential. When'the parallel conductors are placed in close proximity with the axle shaft as it is rotated, the shaft is inductively heated for subsequent quench hardening.

In many instances, an axle shaft incorporates an end mounting flange. In this instance, the crossover conductor adjacent one end of the inductor is magnetically coupled with the flange and the fillet between the flange and the cylindrical portion of the axle shaft. Consequently, this one crossover conductor is essential in heating the area of the flange adjacent its intersection with the cylindrical body portion of the shaft. Since the same current flows through all portions of the inductor, the heating of the fillet area between the flange and cylindrical body portion is somewhat dictated by the heating of the shaft itself by the parallel conductors. In some instances, the flanged portion of the shaft should be heated to a greater extent than can be accomplished by the normal crossover conductor. It has been suggested to extend the crossover conductor into a U-shaped configuration so that the larger current path is defined within the crossover conductor adjacent the flange. However, the increased heating by this arrangement is substantially spaced from the fillet at the intersection ofthe flange and the body portion of the shaft.

The present invention relates to an improved inductor of the type described above with a modified crossover conductor that increases the heating adjacent the intersection of the flange portion and cylindrical body portion without requiring heating of the flange at a distance substantially spaced from the actual intersection of these two portions.

In accordance with the present invention, there is provided an inductor of the general type described above wherein the crossover conductor adjacent the flange is magnetically coupled with the flange and has two diverging legs connected to the respective parallel conductors and a generally arcuate portion connecting the two legs whereby the arcuate portion has a length greater than the arcuate distance concentric with the axis of the cylindrical portion and between the parallel conductors. In this manner, the arcuate portion of the crossover conductor is substantially close to the intersection of the flange and the cylindrical portion of the axle shaft. The shaft is an elongated workpiece which can be defined as a workpiece wherein the cylindrical portion has a length at least ten times its diameter.

The primary object of the present invention is the provision of an inductor of the type extending the length of a rotating workpiece having a cylindrical portion and a flange, which inductor includes a crossover conductor magnetically coupled with the flange and having an increased heating effect in the general area between the flange and the cylindrical portion.

Another object of the present invention is the provision of an inductor of the type extending the length of a rotating workpiece having a cylindrical portion and a flange, which inductor includes a crossover conductor magnetically coupled to the flange with two diverging legs and a generally arcuate portion joining these legs so that the major portion of the crossover conductor is closely spaced with respect to the intersection between the flange and cylindrical portion.

These and other objects and advantages will become apparent from the following description used to illustrate the preferred embodiment of the present invention when taken in connection with the accompanying drawings, in which:

FIG. 1 is a pictorial view illustrating, somewhat schematically, the preferred embodiment of the present invention;

FIG. 2 is an enlarged top plan view showing the embodiment ofthe invention illustrated in FIG. 1;

FIG. 3 is a partial cross-sectional view taken generally along line 3-3 of FIG. 2; and,

FIG. 4 is a cross-sectional view taken generally along line 4-4 of FIG. 2.

Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting same, these figures show an induction heating device A for inductively heating an axle shaft B having an elongated, cylindrical body portion 10 with the central axis a, a flange 12, an intermediate fillet 14 between the flange and cylindrical portion, and terminal center recesses 16, 18. During the heating operation of axle shaft B, the axle shaft is rotated by any appropriate means, schematically represented as rotating means 20. The axle shaft is supported to rotate about axis a on two spaced centers 22, 24.

The induction heating of the axle shaft is accomplished by inductor C including two parallel conductors 30, 32 circumferentially spaced a distance represented by angle 'b. This angle is less than l preferably less than l40. In practice, the angle b is approximately crossover conductors 34, 36 join the ends of the parallel conductors to form an electrical loop. The conductor 30 is separated and joined onto leads 40, 42, connected across the output of an appropriate high frequency power source, schematically represented as generator 44.

In operation, as the workpiece is rotated, the energized inductor C inductively heats the portions of the workpiece spaced from the various conductors. In this manner, the total length of the cylindrical portion 10 is primarily heated by the parallel conductors 30, 32. Flange 12 and fillet 14 are heated, primarily, by the crossover conductor 34. As so far described, inductor C does not differ substantially from known conductors. However, these known conductors, in certain instances, did not sufficiently heat the fillet 14 of the workpiece.

In accordance with the present invention, the crossover conductor 34 is modified to provide diverging legs 50, 52. These legs may extend at various diverging angles; however, in the preferred embodiment of the present invention these diverging legs extend radially outwardly from the axis a as shown in FIG. 4. The ends of the divergent legs are joined by an arcuate portion 54 having a length corresponding to the ar cuate distance inscribed by angle b. This arcuate length of the portion 54 is greater than the arcuate distance between parallel conductors 30, 32. Consequently, a larger current path is coupled with the flange. By providing the diverging legs 50, 52 the arcuate portion 54 is moved downwardly closer to the flange 14 than would be possible if the legs were not divergent. To exhibit this principle, the midpoint of portion 54 is spaced from the cylindrical portion 10 a distance x and the radial height of the flange 12 is y. In practice, x is substantially less than half of y. Also, x is generally less than the diameter of the cylindrical portion 10. Consequently, the arcuate portion 54 is maintained in close proximity with the fillet 14 to effect heating in this area instead of in a remote area of the flange 12.

Having thus defined my invention, I claim:

1. In an inductor for inductively heating a rotating, elongated workpiece having a cylindrical body portion with a central axis and a flange on one end thereof, said inductor extending longitudinally along said cylindrical portion, first and second crossover conductors joining said parallel conductors at their respective ends, and leads for connecting one of said parallel conductors onto a source of high frequency current,

greater than the arcuate distance concentric with said axis and between said parallel conductors.

2. The improvement as defined in claim 1 wherein said parallel conductors are circumferentially spaced, with respect to said cylindrical portion, an angular distance substantially less than 

1. In an inductor for inductively heating a rotating, elongated workpiece having a cylindrical body portion with a central axis and a flange on one end thereof, said inductor extending longitudinally along said cylindrical portion, first and second crossover conductors joining said parallel conductors at their respective ends, and leads for connecting one of said parallel conductors onto a source of high frequency current, said one parallel conductor being interrupted between said leads, the improvement comprising: said first crossover conductor being magnetically coupled with said flange and having two diverging legs connected to the respective parallel conductors and extending outwardly from said workpiece and adjacent said flange and a generally arcuate portion connecting said two legs at a position spaced only slightly from said parallel conductors whereby said arcuate portion has a length greater than the arcuate distance concentric with said axis and between said parallel conductors.
 2. The improvement as defined in claim 1 wherein said parallel conductors are circumferentially spaced, with respect to said cylindrical portion, an angular distance substantially less than 180*. 